1. Field of the Invention
This invention relates to the processing of multi-filament and mono-filament synthetic fibers particularly polyester and nylon fibers with fiber lubricants which are applied as spin-finishes subsequent to extrusion of the fibers from the spinneret.
2. Description of the Prior Art
In the production of polyester and polyamide filaments, the addition of a lubricant after extrusion from the spinneret is essential in order to process the emerging filaments into fibers. Since in many instances the filaments are ultimately subjected to a false twist texturing process in which the fibers are stretched after being contacted with a heated metal plate, in addition to the lubricity properties required to avoid breaking the fibers during such processing, relatively high oxidation stability is required in the fiber lubricant. It is known to utilize polyoxyethylene compounds as fiber lubricants as well as heteric polyoxyalkylenes derived from the random polymerization of ethylene oxide or 1,2-propylene oxide. The heteric polyethers obtained by copolymerizing ethylene oxide or propylene oxide with tetrahydrofuran which are disclosed in Japanese Patent Announcement No. 213-1977 have a molar ratio of ethylene oxide or propylene oxide to tetrahydrofuran of between 9/1 to 1/4. Ethoxylated polybutylene glycols are disclosed as fiber lubricants in U.S. Pat. No. 3,834,935, but these polyethers are based on butylene oxides in which the oxygen atom is bonded to each of two contiguous carbon atoms as represented by 1,2- or 2,3-butylene oxide.
Block copolymers of tetrahydrofuran and ethylene oxide are disclosed for use as surfactants by Kuwamura et al in the Journal of the American Oil Chemists Society 48, 29 (1971). The uses suggested for these surface active tetrahydrofuran/ethylene oxide block copolymers are in the area of surfactants, emulsifiers and dispersing agents. Use of these copolymers as lubricants for textile fibers is not disclosed or suggested. The physical properties of the block copolymers are described in Kuwamura et al as resembling those of the ethylene oxide/propylene oxide block copolymers having comparable molecular weight of the hydrophobe and ethylene oxide content.